Recently, there is increasing awareness for security, such as privacy protection, blocking leaks of corporate secrets, and the like. The increasing awareness raises the necessity for a system that can protect confidential contents recorded in, e.g., a document (paper), and that enables only a particular person to access the data when transmitting data on a piece of paper. Since such system does not let a third person see data recorded in a document, it can prevent careless data leaks.
In order to decrypt data embedded in a document by the system, a Public Key Infrastructure (PKI) server that determines disclosure of the data recorded in a document, or an authentication server, and a decryption engine that deciphers encrypted data are essential.
For instance, encrypted electronic data cannot be decrypted (decoded) without key data used in the encryption. In other words, having the key data itself is the authentication processing. This is because, in electronic data encryption, electronic data itself is invariable and can always be decrypted as long as there is key data.
Meanwhile, when data is embedded in a document (paper), employed is an embedding method having as much resistance as possible using a cyclic pattern. In other words, it focuses on accurate detection, analysis, recognition and extraction of data embedded in a document.
In the meantime, it is simpler to manage an electronic signature on a server since it is electronic data supposed to be handled on a network. On the contrary, authentication in a portable physical medium such as paper is more conveniently managed by a serverless system that does not require network intermediation. For instance, Japanese Patent Application Laid-Open No. 2004-058410 discloses a serverless system for reading a document having embedded secret data, which enables a particular authenticated user to access the secret data.
However, when realizing the serverless system disclosed in Japanese Patent Application No. 2004-058410, data embedded in a document relies on the authentication system and security system. In other words, in the serverless system, the data embedded in a document cannot be disclosed in a place where the same authentication system and the same security system do not exist.